Wind power becomes more and more important. Parallel with the increasing significance of wind power wind turbines are getting larger and larger, which makes it more difficult to transport the large, in general preassembled and integrated wind turbine parts from the place of manufacture to the sites of erection, this can be onshore or offshore.
Normally a wind turbine comprises a few larger parts in form of the blades, the hub, the tower and the nacelle. Particularly the nacelle comprises a number of integrated main components such as a main shaft, a main bearing assembly, a gearbox, a generator, some power/control components, a transformer, a cooling system and so on, which are all arranged on a common bedplate and in a common nacelle housing. The bedplate has a yaw system to orient the nacelle towards the wind direction. Typically the nacelle is completely preassembled at the place of manufacture.
When a wind turbine is erected the blades, the hub, the tower and the preassembled nacelle are transported to the site of erection. The tower is erected, the nacelle is mounted on the tower, the hub is mounted on the nacelle and the blades are attached to the hub by means of at least one crane. Thereby not only the transportation in particular the transportation of the large and heavy nacelle is difficult, but also the mounting on the tower, which requires sufficient crane capacity to handle the complete nacelle weight.
Moreover the servicing of such a wind turbine is often very complicated and time consuming, in particular when one or more components of the nacelle have to be replaced.